A multilayer coil disclosed in Japanese Unexamined Patent Application Publication No. 2000-133521 is known as one kind of electronic components according to the related art. The multilayer coil disclosed in Japanese Unexamined Patent Application Publication No. 2000-133521 will be described below. FIG. 5 is a sectional view illustrating a configuration of a multilayer coil 500 disclosed in Japanese Unexamined Patent Application Publication No. 2000-133521.
As illustrated in FIG. 5, the multilayer coil 500 includes a laminated body 512, outer electrodes 514a and 514b, an insulating resin 518, and a coil L. The substantially rectangular-parallelepiped laminated body 512 includes a plurality of insulating sheets laminated on one another. The helical coil L, included in the laminated body 512, includes a plurality of connected coil conductor patterns 516. As illustrated in FIG. 5, the coil conductor patterns 516 are exposed from lateral faces of the laminated body 512.
The outer electrodes 514a and 514b on upper and lower faces of the laminated body 512, respectively, are connected to the coil L. The insulating resin 518 is provided on the lateral faces of the laminated body 512 to cover parts of the coil conductor patterns 516 exposed from the lateral faces of the laminated body 512.
Since the coil conductor patterns 516 extend to outer peripheries of the corresponding insulating sheets in the multilayer coil 500 having the foregoing configuration, an inside diameter of the coil L can be increased. Furthermore, since the insulating resin 518 covers the lateral faces of the laminated body 512 in the multilayer coil 500, a short circuit between the coil conductor patterns 516 and patterns on a circuit board is prevented.
However, in the multilayer coil 500 disclosed in Japanese Unexamined Patent Application Publication No. 2000-133521, the insulating resin 518 relatively easily peels off from the laminated body 512. More specifically, the laminated body 512 is formed of a magnetic material, such as ferrite, whereas the insulating resin 518 is formed of a material, such as an epoxy resin. Because the laminated body 512 and the insulating resin 518 are formed of different materials, adhesion between the laminated body 512 and the insulating resin 518 in the multilayer coil 500 is relatively low. Thus, the insulating resin 518 may unfortunately peel off from the laminated body 512.